Rotary wick wiper apparatus for treating plants

ABSTRACT

The invention provides a rotary wick wiper apparatus (10) for plants, of the type wherein a rotor assembly (12) is operatively connected to a motor (15) whereby it may be rotated about an axis (13) disposed substantially vertically in use, the rotor assembly having a wick (17) beneath it for plant-wiping function and arranged to receive liquid from a reservoir (19) above the bottom of the rotor assembly (12) and movable with the rotor assembly; characterized in that the reservoir (19) has an air vent (28) on a portion thereof which is normally elevated and disposed inwardly relative to the rotor assembly axis of rotation, the air vent (28) being connected to one end of an air tube (29) of small diameter extending circuitously around the rotor assembly (12) and having its other end providing an air-intake opening (33) on a part of the rotor assembly disposed outwardly of the air vent (28) relative to the axis of rotation (13).

TECHNICAL FIELD OF THE INVENTION

THIS INVENTION relates to improvements in rotary wick wiper apparatusfor treating plants, and it has particular reference to known types ofapparatus such as a ropewick applicator for applying herbicides and thelike to annual and perennial weeds by a rotary wiping action.

BACKGROUND ART

One very, successful form of apparatus of the abovementioned generaltype is that sold under the registered trade mark "WEEDBUG" and thesubject of Australian Patent No. 589361. Apparatus according to thatinvention may take various forms, including a tractor-mounted machineideally suited to the application of weed-killing chemicals up to andaround tree trunks, even in windy conditions. Typically the machine usesropewick application from rotating discs or rotors fitted to adjustablearms so that the disc or rotor speed controls the chemical flow. Eachrotor or disc has a cover assembly to roll around trees on soft bumpedges, protecting the bark from abrasion while the disc works under thecover assembly. Such a machine can be operated under low hanging trees,and it may employ a single applicator rotor if desired, but usually twoor more will be incorporated in each such machine which can also be usedeffectively along fencelines, road or pond edges, and in open areasrequiring weed control.

Reference to the said Australian patent specification No. 589361 willshow that the rotor has means whereby it may be rotated about an axisdisposed substantially vertically in use and having a bottom discthrough which the wick means extend for operation therebeneath, therebeing in practice a plurality of equally spaced wicks passing sealablythrough apertures in the disc from an annular reservoir above the discand rotatable therewith. FIGS. 1 and 3 of the drawings of the earlierpatent specification show basic requirements for the reservoir, whileFIG. 4 shows an annular structure using the disc itself as a lower partof the reservoir. The arrangement for the wicks as shown in FIG. 5 ofthe earlier patent specification has been found very satisfactory inrelation to design details, but most other components can be variedconsiderably within the broad ideas disclosed therein.

While the machines of the aforedescribed types, such as those sold underthe registered trade mark "WEEDBUG", have been found very effective inachieving their objects, we have found that the continuous andconsistent or steady application or flow of liquid through the wicks canbe hampered by the fact that the reservoir is sealed to atmosphereexcept at the apertures through which the wicks pass to beneath therotor disc. It will be appreciated that the withdrawal of liquid fromthe reservoir causes the formation of vacuum conditions which arecurrently relieved only by drawing back of air to the reservoir throughthe wicks or their mountings. The provision of a vent normally presentsdifficulties because liquid could be expelled centrifugally therethroughmost undesirably. Also its location must not only be at an elevatedposition above liquid level in normal use, but it must take into accountthe fact that the rotors when inoperative can be swung upwards on themachine with the axis of rotation becoming or approaching horizontal andfacilitating spillage through the air vent.

Our present invention has been devised to overcome or ameliorate thedifficulties currently experienced as abovementioned, and it has for itsprincipal object the provision of vent means for the reservoir wherebythe desired venting will be achieved but without the disadvantageousconsequences of a normal venting system as aforestated. Other objects ofthe invention are to provide a novel venting arrangement which can beput into effect without substantially altering existing design featuresof the machines. A further object is to provide such improvements whichwill be of simple and inexpensive form, which may be quickly and easilyfitted, and which will prove reliable and durable in use. Other objectsand advantages of the invention will be clear from the subsequentdescriptions.

DISCLOSURE OF THE INVENTION

With the foregoing and other objects in view, our invention residesbroadly in a rotary wick wiper apparatus for plants, of the type whereina rotor assembly is operatively connected to means whereby it may berotated about an axis disposed substantially vertically in use, therotor assembly having wick means beneath it for plant-wiping functionand arranged to receive liquid from a reservoir above the bottom of therotor assembly and movable with the rotor assembly; characterised inthat the reservoir has an air vent on a portion thereof which isnormally elevated and disposed inwardly relative to the rotor assemblyaxis of rotation, said air vent being connected to one end of an airtube of small diameter extending circuitously around the rotor assemblyand having its other end providing an air-intake opening on a part ofthe rotor assembly disposed outwardly of said air vent relative to saidaxis of rotation.

Preferably, the reservoir is of continuous annular form about the axisof rotation and forming part of said rotor assembly, the air vent beingprovided on a removable annular lid of the rotor assembly. It is alsopreferred that the lid is of disc-like annular form defined by andbetween concentrically circular lid edges beneath which are sealingstrips for securement to upstanding rims of the inner and outerperipheries of the annular reservoir.

Suitably, the air vent in the annular lid is an aperture through the lidnear to its inner periphery, said air tube being mounted on the lid andhaving its one end sealably connected to said aperture. Preferably insuch an embodiment, the air tube extends outwardly from the air ventaperture and then through at least one turn around an outer part of thelid before terminating in said air-intake opening near to the outer edgeof the lid.

In a preferred form of the invention, the air tube is turned through twofull concentric coils between its end which is connected to the air ventaperture and its end which constitutes the air-intake opening. In thatevent, suitably the air tube at that end thereof which is connected tothe air vent aperture extends radially along the top surface of the lidand then turned through a curve over approximately ninety degrees beforeextending through said two full concentric coils to the other end whichconstitutes the air-intake opening.

In all cases it is preferred that the tube is secured to the lid byreleasable clip means and extends around the lid from its inner to outerends in the direction of rotation of the rotor assembly. Other featuresof the invention will be hereinafter apparent.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more readily understood and put intopractical effect, reference will now be made to the accompanyingdrawings, wherein:

FIG. 1 shows in side elevation part of a known type of rotary wick wiperapparatus but fitted with the reservoir-venting means according to thepresent invention;

FIG. 2 is a sectional side elevation corresponding to FIG. 1, and

FIG. 3 shows in plan view the reservoir lid and vent arrangements of theapparatus of FIGS. 1 and 2.

DETAILED DESCRIPTION OF THE INVENTION

Referring initially to FIGS. 1 and 2 of the drawings, the rotary wickwiper apparatus 10 is basically the same as in the Australian patentspecification No. 589361 in that the rigid frustro-conical housing 11has therebeneath a rotor assembly 12 which is rotatable about an axis 13by being secured to rotatable shaft 14 of a motor 15. The latter isdriven by hydraulic means 36 extending to a power source along with themounting arm 37 leading from the central hub section 38. The rotorassembly 12 has a bottom disc 16 shaped to carry wicks therebeneath, onewick 17 being illustrated where it sealably passes through an aperture18 into the reservoir 19.

It will be noted that the bottom disc 16 has portions 20, 21 and 22defining bottom sections of the reservoir 19 which has inner and outerannular rims 23 and 24 forming side walls. The upper end of thereservoir 19 is closed by a lid 25 having the novel features of thepresent invention. The other components will be self-evident, therebeing shown other openings or apertures 18 for further wicks to form apattern, along the lines of that illustrated in FIG. 5 of the saidearlier patent.

Referring now to FIG. 3, the lid 25 may be plain on its underside orprovided with sealing ribs for strengthening purposes and so that it canengage on and be secured by screws (not shown) to the top faces of therims 23 and 24, such sealing ribs being concentric at the inner andouter peripheries 26 and 27 of the annular lid 25. Near to the innerperiphery 26, there is an air vent aperture at 28 in which is securedthe inner end of a small-diameter tube 29 which extends more or lessradially outwards and then through about ninety degrees in a non-sharpbend 30 before continuing through two concentric loops 31 and 32 to aterminal opening or air intake 33. The direction of rotation of the lid25 and rotor assembly 12 is indicated by the arrow 34, and it will beclear that there is a resultant tendency for liquid in the tube 29 to beurged back to the reservoir as rotation takes place. FIG. 3 alsoindicates the positions of clip means 35 spaced around the lid, such asmetal clips held by middle screws, but any other form of clip wouldsuffice.

It will be clear that the air vent aperture 28 will be uppermost andabove liquid level in the reservoir 19, while its inner locationprevents liquid reaching it through centrifugal force, and the result ofvacuum avoidance will be achieved. If the apparatus is raised to bringthe rotation axis 13 to horizontal or the like, the continuous loops 31and 32 provide the equivalent of "air locks" to prevent liquid runningout in a syphon manner as would otherwise occur, and when verticaldisposition of the axis 13 is restored, full equilibrium conditions arerestored. Thus, the tube 29 provides the function of a valve but withoutthe disadvantages attendant upon mechanical contrivances which aresubject to sticking or clogging. Our invention will admit air to theextent necessary according to desired design features and will beeffective at all times and at all angles of operation.

In practice, the reservoir is filled through the wick aperture to alevel which is required, being much less than totally filled which wouldbe both unnecessary and inducive of problems. The length of the tube 29should be sufficient to cater for expansion of air therein under heatedconditions, and it can be made in any number of loops, two or more beingpreferable. The tube may by way of example be 3 mm to 4 mm in internaldiameter, and it may take other shapes which are circuitous or tortuousapart from that illustrated. The non-sharp bend arrangements ensure asmooth transition of flow of any liquid which enters or is trappedtherein according to prevailing conditions, as opposed to undesirablesharp angles. Rotation of the rotor assembly and reservoir lid willalways be in the same direction, urging flow back to the reservoir ofliquid in the tube. The diameter of the tube can be as desired but isselected so that clogging by dust or other material is resisted. The lidmay suitably be made of polyurethane but any material will suffice,while its outside diameter in this instance is about 40 cms forillustrative purposes.

Various other modifications of the invention are contemplated which willbe apparent to persons skilled in the art and which can be resorted towithout departing from the spirit and scope of the invention as definedby the appended claims.

I claim:
 1. A rotary wick wiper apparatus for plants, of the typewherein a rotor assembly is operatively connected to means whereby itmay be rotated about an axis disposed substantially vertically in use,the rotor assembly having wick means beneath it for plant-wipingfunction and arranged to receive liquid from a reservoir above thebottom of the rotor assembly and movable with the rotor assembly;characterised in that the reservoir has an air vent on a portion thereofwhich is normally elevated and disposed inwardly relative to the rotorassembly axis of rotation, said air vent being connected to one end ofan air tube of small diameter extending circuitously around the rotorassembly and having its other end providing an air-intake opening on apart of the rotor assembly disposed outwardly of said air vent relativeto the said axis of rotation.
 2. A rotary wick wiper apparatus accordingto claim 1, and further characterised in that the reservoir is ofcontinuous annular form about the axis of rotation and forming part ofsaid rotor assembly, the air vent being provided on a removable annularlid of the rotor assembly.
 3. A rotary wick wiper apparatus according toclaim 2, and further characterised in that the lid is of disc-likeannular form defined by and between concentrically circular lid edgesbeneath which are sealing strips for securement to upstanding rims ofthe inner and outer peripheries of the annular reservoir.
 4. A rotarywick wiper apparatus according to claim 3, and further characterized inthat the air vent in the annular lid is an aperture through the lid nearto its inner periphery, said air tube being mounted on the lid andhaving its one end sealably connected to said aperture.
 5. A rotary wickwiper apparatus according to claim 2, and further characterised in thatthe air vent in the annular lid is an aperture through the lid near toits inner periphery, said air tube being mounted on the lid and havingits one end sealably connected to said aperture.
 6. A rotary wick wiperapparatus according to claim 5, and further characterised in that theair tube extends outwardly from the air vent aperture and then throughat least one turn around at outer part of the lid before terminating insaid air-intake opening near to the outer edge of the lid.
 7. A rotarywick wiper apparatus according to claim 6, and further characterised inthat the air tube is turned through two full concentric coils betweenits end which is connected to the air vent aperture and its end whichconstitutes the air-intake opening.
 8. A rotary wick wiper apparatusaccording to claim 7, and further characterised in that the air tube atthat end thereof which is connected to the air vent aperture extendsradially along the top surface of the lid and then turned through acurve over approximately ninety degrees before extending through saidtwo full concentric coils to the other end which constitutes theair-intake opening.
 9. A rotary wick wiper apparatus according to claim8, and further characterized in that the tube is secured to the lid byreleasable clip means and extends around the lid from its inner to outerends in the direction of rotation of the rotor assembly.
 10. A rotarywick wiper apparatus according to claim 5 and further characterised inthat the tube is secured to the lid by releasable clip means and extendsaround the lid from its inner to outer ends in the direction of rotationof the rotor assembly.